Particle pollution can cause early death and heart attacks, strokes and emergency room visits.
The nation has the Clean Air Act to thank for decades of improvements in air quality. This landmark law has successfully driven pollution reduction for over 50 years.
Millions of people are especially vulnerable to the effects of air pollution, including children, older adults and people with lung diseases such as asthma and COPD.
Breathing in particle pollution can increase the risk of lung cancer.
People who work or exercise outside face increased risk from the effects of air pollution.
Ozone and particle pollution are both linked to increased risk of premature birth and lower birth weight in newborns.
Climate change enhances conditions for ozone pollution to form and makes it harder clean up communities where ozone levels are high.
People of color and people with lower incomes are disproportionately affected by air pollution that puts them at higher risk for illness.
Air pollution is a serious health threat. It can trigger asthma attacks, harm lung development in children, and even be deadly.
Recent updates to the Air Quality Index give the public more accurate information about the health risk from air pollution, and when to take measures to protect themselves on bad air days.
Nearly four in ten people in the U.S. live where the air they breathe earned an F in "State of the Air" 2024.
If you live or work near a busy highway, traffic pollution may put you at greater risk of health harm.
Particles in air pollution can be smaller than 1/30th the diameter of a human hair. When you inhale them, they are small enough to get past the body's natural defenses.
Climate change increases the risk of wildfires whose smoke spreads dangerous particle pollution.
Policymakers at every level of government must take steps to clean the air their constituents breathe.
You can protect yourself by checking the air quality forecast in your community and avoiding exercising or working outdoors when unhealthy air is expected.
More than 131 million people live in counties that received an F for either ozone or particle pollution in "State of the Air" 2024.
Breathing ozone irritates the lungs, resulting in inflammation—as if your lungs had a bad sunburn.
Nearly 44 million people live in counties that got an F for all three air pollution measures in "State of the Air" 2024.
Particle pollution exposure from wildfire smoke harms health in ways that range from mild irritation to serious illness and premature death.
“State of the Air” grades are based on the number of days a county’s air reaches unhealthful levels on the Air Quality Index. Each unhealthy air day is given a weighted score, with orange days given a weight of 1, red days 1.5, purple days 2 and maroon days 2.5. Those daily scores are added up and divided by 3 to get a weighted average that is then assigned a grade. For year-round particle pollution, grading is based on the national standard for annual PM2.5 of 9 μg/m3. Counties for which EPA lists a design value of at or below the standard are given grades of “Pass.” Counties at or above 9.1 μg/m3 are given grades of “Fail.”
Review our methodology for a full explanation of data sources and calculations utilized to assign grades for the air you breathe.
The colors used in “State of the Air" are based on the Air Quality Index, which assigns six different levels of health concern to increasing concentrations of air pollution. Each category has a specific color. “State of the Air” only includes the four levels that are considered unhealthy: Orange for “unhealthy for sensitive groups,” Red for “unhealthy,” Purple for “very unhealthy,” and Maroon for “hazardous.”
Review our methodology for a full explanation of data sources and calculations utilized to assign grades for the air you breathe.
Ozone air pollution, sometimes known as smog, is one of the most widespread pollutants in the United States. It is a powerful lung irritant. When inhaled into the lungs, it reacts with the delicate lining of the airways, causing inflammation and other damage that can impact multiple body systems. Ozone exposure can also shorten lives.
Your health is heavily impacted by air pollution. Learn more about how pollutants affect the body, and which groups of people are most at risk.
Particle pollution is a deadly and growing threat to public health in communities around the country. The more researchers learn about the health effects of particle pollution, the more dangerous it is recognized to be. Short-term spikes in particle pollution that last from a few hours to a few days can kill. Most premature deaths are from respiratory and cardiovascular causes. Spikes in particle pollution also have many other harmful effects, ranging from decreased lung function to heart attacks.
Your health is heavily impacted by air pollution. Learn more about how pollutants affect the body, and which groups of people are most at risk.
Particle pollution is a deadly and growing threat to public health in communities around the country. The more researchers learn about the health effects of particle pollution, the more dangerous it is recognized to be. Breathing particle pollution day in and day out can be deadly. Research has also linked year-round exposure to particle pollution to a wide array of serious health effects at every stage of life.
Your health is heavily impacted by air pollution. Learn more about how pollutants affect the body, and which groups of people are most at risk.
All of the millions of Americans living in places with failing grades for unhealthy levels of ozone or particle pollution are at risk of harm to their health. But some groups of people are especially vulnerable to illness and death from their exposure.
Your health is heavily impacted by air pollution. Learn more about how pollutants affect the body, and which groups of people are most at risk.